US anthrax strains matched

Eight people have been infected and 38 exposed

Tests have shown that strains of anthrax sent to NBC television in New York, the Sun tabloid in Florida and to the Senate in Washington could have come from the same source.

US Homeland Security Chief Tom Ridge said "the tests to date have concluded that the strains are indistinguishable". He said the anthrax had not been "weaponised" - altered to make it spread more easily in the air.

The recipient of the letter in Argentina is said to be not at risk

Reports from South America say anthrax-tainted letters have also been received there.

A letter sent from Miami to an individual in Buenos Aires showed the presence of anthrax spores, Argentine Health Minister Hector Lombardo said, confirming test results.

And the New York Times said on Friday that its reporter in Rio de Janeiro, Brazil, had received a letter that tested positive for spores "consistent with anthrax," Reuters news agency reported.

Earlier, the Kenyan Government said four people had been exposed to anthrax bacteria in a letter posted from the US.

Eighth infection in US

US health officials said on Friday that a second postal worker in New Jersey had tested positive for skin anthrax, bringing to eight the number of people diagnosed with the disease in the United States.

Our biggest problem is fear... We are resolute, we will not flinch, we will not bend, we will not swerve

CBS news anchor Dan Rather

The 35-year-old man is taking antibiotics in hospital and is expected to recover. Pennsylvania Department of Health spokesman Richard McGarvey said "it isn't life-threatening in any way".

The man worked at a regional mail centre in Hamilton that handled anthrax-tainted letters posted to NBC anchorman Tom Brokaw and Senate Majority Leader Tom Daschle in Washington.

Earlier this week a female postal worker was diagnosed with skin anthrax.

New York Post case

It was confirmed on Friday that a woman working for the New York Post had contracted skin anthrax.

With anthrax-lined letters being sent abroad, no country feels safe

A statement by the newspaper's publisher said the employee was "already regarded as cured".

Speaking at a White House press conference, the homeland security chief said: "I wish I could tell you that we've seen the end of it, but we obviously are preparing for more.

"That's why we've decided to increase the supply of the antibiotics and that's why we are pursuing every lead as aggressively as possible."

New Jersey connection

The White House has yet to name a suspect for the anthrax attacks.

According to the New York Times, the tainted letters sent to Senator Tom Daschle and NBC news announcer Tom Brokaw were sent from a 1.6 sq km area of West Trenton, New Jersey, where some hijackers and suspected members of al-Qaeda lived.

The infected New York Post employee is the fourth case of anthrax in New York City - all involving media companies.

At least 38 people have been exposed to the bacteria.

All three major TV networks in New York City, the New York Post, the Capitol Hill complex in Washington and a tabloid newspaper company in Florida have now become sites of anthrax infection.

Taleban denial

Earlier on Friday, the Taleban ambassador to Pakistan denied any link to the anthrax attacks in the US.

We don't even know what it is

Taleban envoy Mullah Abdul Salam Zaeef

Mullah Abdul Salam Zaeef said the Afghan movement did not even know what anthrax was.

FBI director Robert Mueller said the US was offering $1m for information on who was behind the anthrax attacks.

The US postal service is sending cards to every home and business - 147 million addresses - telling people how to deal with suspicious post.

Health authorities and emergency services in New York complained they were being swamped by nervous members of the public demanding nasal swabs and doctors were urged not to prescribe the antibiotic Ciprofloxacin - used to treat anthrax - without good medical reasons.

The drug's main manufacturer, Bayer, announced it would treble production.